1. Technical Field
The present invention relates to a technique for ejecting fluid from an ejection head.
2. Related Art
A printer (so-called ink jet printer) which prints an image by discharging ink onto a print medium is capable of easily printing a high quality image. Therefore, the printer is widely used as an image output unit nowadays. It is considered that various types of precision parts such as an electrode, a sensor, a biochip can be easily manufactured by applying the technique as follows. That is, such precision parts can be manufactured by ejecting various types of fluids prepared to an appropriate component (the various types of fluids include liquid in which fine particulates of a functioning material are dispersed or semiliquid such as gel, for example) in place of ink onto a substrate.
In order to eject fluid properly, a dedicated ejection head on which fine ejection nozzles are provided is mounted on the ink jet printer or the fluid ejecting apparatus. A platen portion which supports a medium such as a printing paper is provided at a position opposed to the ejection head. Fluid is ejected from the ejection nozzles in a state where the medium is kept at an accurate position with the platen portion so that the fluid can be ejected onto the medium at an accurate position. When the characteristics of fluid have been changed because the fluid is dried in the ejection head, or in some case another trouble may happen in the ejection head, the fluid may not be ejected normally in some case. In order to deal with the problem, a cap which is connected to a suction pump is provided at a position different from that of the platen portion. Therefore, when the characteristics of the fluid in the ejection head have been changed, the ejection head is moved to the position of the cap from the position of the platen mechanism. Then, the cap is pressed against the ejection head so as to drive the suction pump. This makes it possible to suck the fluid of which characteristics have been changed from the ejection nozzles and discharge the fluid.
Further, when a large-sized ejection head is mounted on the fluid ejecting apparatus, it is difficult to move the ejection head from the position of the platen portion to that of the cap in some case. Then, a technique in order to deal with the problem is proposed (JP-T-2003-534165). In the technique, a platen portion and a cap are provided on surfaces of a rotation body provided so as to be opposed to the ejection head and the rotation body is rotated so that the platen portion and the cap can be easily switched without moving the ejection head.
However, in the proposed technique, there has been a problem that fluid in the cap is dried while the cap is not used. If the rotation body is rotated so as to switch the cap to the platen portion after the cap is used, inner portion of the cap is opened to the outside air. Therefore, a volatile component is volatilized from fluid adhered to the inner portion of the cap and the fluid is dried. This results in a disadvantage that the fluid is firmly fixed to the inner portion of the cap as to obstruct a suction flow path of the suction pump. It can be considered that the rotation body is rotated after fluid in the cap is completely discharged, as a matter of course. However, the fluid adhered to the inner portion of the cap cannot be completely discharged easily in fact.